The present invention is in the field of chemical reaction vessels. More specifically this invention relates to sealing of reaction vessels when adding or removing samples.
In general, addition of reagents to a reaction vessel is performed either by injection with a syringe and cannula through a septum, or by opening a port mechanically and adding the material through the opening. Another method is to use non-septum piercing disposable pipette tips which are thrust through prescored septa. This method is used when high accuracy and low cross contamination is desired, however, the essential prescored septum suffers from poor sealing properties.
In the case of addition through the septum, many problems routinely emerge. There are only a limited amount of times a septum can be pierced before it starts to leak at an unacceptable rate. Even one piercing may lead to a leak which could cause the loss of reagent and/or contamination, and change the outcome of an experiment in an unacceptable way. In the event that the tainted experimental result is not appreciated, false conclusions could be reached. One way the prior art has attempted to overcome this is by replacing the septum after use in a counterflow of inert gas. This is a time consuming and complex procedure. Further, septa are commonly abraded by the piercing action, resulting in septa particulates contaminating the experiment. Also, where the reaction vessel is subjected to conditions which produce a relatively high pressure in the vessel, this pressure commonly needs to vent to achieve accurate reagent delivery, and the way the septa commonly seals around the puncturing needle does not allow for adequate venting. In these situations, special grooved needles may be used, to allow for venting when the needles pierce the septa. However, these needles are more expensive, and contaminates may get caught in the grooves affecting the experiment.
Opening the port mechanically requires external actuation, which becomes challenging, complicated, and expensive with larger arrays of vessels. This is further complicated because any delay in closing the port allows reagents to potentially escape.
A sealing mechanism for reaction vessels is desired which would not deteriorate over time and use, which would not contaminate the reagents, which could allow for venting of pressure when necessary, which is self-actuating and self-sealing, and which would be easily adapted to large arrays of reaction vessels, such as those used in combinatorial chemistry.